Heat settable butadiene-styrene coating mixtures



' y the diluent to 'ato' Unite Sat 3,170,806 HEAT SETTABLE BUTADIENE-STYRENE COATING MIXTURES Joseph G. Svrchek, Hinsrlale, Ill.,assignor to Dearhom Chemical Company, Chicago, Ill., a corporation'of ylllinois 7 No Drawing. Filed Feb. 1, 1963, Ser. No. 255,647 a I 4 Claims (Cl. 106.28;5) 1 v The present invention deals with an improved composition which' is rsettable by heat into an impervious protective coating. While the'composition of the present invention is useful jn'protecting many types of articles against-mechanical damage, corrosion, and the like, it

is particularly useful in the fieldof coating pipes which are to'be buried underground. A The most prevalent methods for protecting pipe which is'to -be buried underground involve the application of 'hot coatings such as coal tar, asphalt, or 'wax to the surface of the pipe followed by a spiral' wrap. While these coating systems are relatively inexpensive raw ma-; 'terials, a substantial amount of labor is involved in ap plying them to the pipe: and then the protection which" they.-.atford is, not j -las great as would be desiredqThechemical and electrical properties of such coatings'on pipe are not completely satisfactory and corrosion of the pipe occurs withflsufiicient frequency that these methods of pipe protection are still less than-Wholly satis- "factory; Hot applied coating systems are also liable to damage during rtransporfi and. damage by back-fill ma terials used'ongthe'job site. The coatings'are alsoL sub-' ject todainagle 'bybending of the pipe prior to -laying,

"ice

conic acid, acrylic acid or estersthereof in small amounts. They may also contain small amounts of alkylated phe nols or other promoters; The copolymers may also containrnodifiers such as acrylic nitriles! alkyl acrylates, vinyl acetate, vinyl ketones, cinnamaldehyde, thioglycolic acid, and the like. 7 The copolyrners mayalso contain bodying agents such'as inaleic anhydride.

j i The butadiene and styrene may beeopolyrrierized in 1 the presence of sodium and a reaotiondiluent 'such as aliphatic hydrocarbon at temperatures ranging from about '25" C. to 95 C. The copolymers are then partly oxidized usually by air blowing until the material absorbs from about 5% to 20% of its weight in. oxygen.

7 This partial oxidationresults in the production bf polar and are subjectfito"disbondingibecause of weathefi ex -x trem'es orsoil stresses Substantial irnprovements in the art of protecting pipe have been achieved 1 through "the :rprocessj' described in US. PateIitLNOI' 3,023,257 issued"August 3,1962, and

assigned tothe same assigneefas the present; applica-' tion. Th t patent describes the applicat-ion of. heat rej'acti'vefp olymers to; surfaces andinvolves spraying aheat' reactive,- partly polymerized c'o'polymer ;.wit h aliammable.

tinuouslfilm, the copolyrner {is completely set to anflinfi'usiblekoating which ompletelyresistant' to" attack chemicals; soil .bacter1a; ;and electrolytic corrosion.

liquid diluent atia temperature above: the fiashpointpf iz'e the coatingJcompositiomjwhere i i h :gupon the "resulting spray isdirected thrpu'gh an envelope of flamefandjheat directed 'at' the surface: wee coated. f

' I -.'Wl1ilein the zone of flame andj heat; theg polyrnerization of 'copolyrner. continues at a'rapidl-rate sothat shortly I l 7 after :applicationfto the ,surface-inthe form or a com Most 'of the commercial applicationsj of the-shame have involvedthe use of commercially available drying 'oils embodying partly n oxidized butadiene-fstyrene icepolymers sold commercially under the""'tradem a'rks spraying processdescribed "in the aforementioned patent Buton 206 and Buton 30031 The composition-also contains a mixture of solvents,-particularlyxylenes and aliphatic alcohol such 'as' isopropanol. The butadienestyrene copolymers contain about -to 35%. butadiene and -15- to 25% styren'ie. They 'niay-fbef prepared in -a;

} number of manners includingreaction of 'the monomers in th'e 'presence. of sodium; The copolymers' may con- 'tain hardness modifying agents ,such Iasimalei'cl acid,

tumariciacid, thi oglycolic acid,fthios ali cyclic acid, Inercaptophthalic acid, itaconic acid,- mesaconic-=aoid, citra coating, wheni se't. 4 a 3 A L 1 v Anotherfl obj'ectof the invention is to provide an imltofofei been: common. 3 I n-accordance with-the groups in the molecule including hydroxyl groups and carboxy groups. The partly oxidized material is Sllfilcientlyacicl to have an acid number on the order of f5'to '18-. r V 1 f The. copolymer 'is dissolved in an aromatic hydrocarbon'solv'ent during oxidationjby blowing. Some of the solvent is then strippedoifleaving a solids content ofjabout 58 60%. Enough .isopropanol,isltiiens added to produce a composition having about; 50%. solidsb jg :IWhile the use ;of' the aforementioned'lpartly oxidized 25- r'naterialhas been found to be satisfactpryi fortthe' purposes intended, continued researeh-has sho n' that the P properties of the coating" can be substantiallyimproved, and the eeo'nornies of the process improvedbymodification of the composition in the manner-tube described.

positions heretofore employed.

till another object ot the invention is toprovideim V proved coat-ingcompositionsincluding a combination of a butadiene styreneicopolyrner and a partly oxidized butadiene-styrenecopolyrnerigto provide .p'roved coating composition of butadiene-sq rene;jcopolyjmersandfderivatives Whichjmakes it ossible to=;secur'e ,j-a greater solidsdeposition 'on the 'articlesthan hasgh ere ene styrene copolymer having from 7510 butadiene and 15 to 25% styrene. The material is substantiallycnon acid, as indicated by itsaoidnumber of about 0; It exists as a viscous liquid whichi's'highly unsaturated, having an iodine number of about 300. Its molecularweight ranges up tol0,000, and typically may extend-from 8,000 to 10,000. I have found that the com-bin'ationof this unoxidized copolymer with the partly oxidized copolymer Patented Feb. 23,1965 I An object. of the-:present invention, is to provide an 1 improved liquidgcoating composition; whiehf. is set-tab le,

. by heat to an'impe'rvious coating. 1 j 4 y A further objectofithe invention is to provide an improvedbutadieneetyrenecopolyrner compositionwhich H is significantlyless brittle iwhen setthan similar com-1 Y present'invention, I combine a. flpartly o'xidized copolymer fof the type describeclf in the I preceding portions of the specification with'an unoxidized copolyrner 'of the same general descriptiongieg a butadicopolymerized solids.

coated, and that the resultant coating is less brittle than occurs through the use of the partly oxidized copolymer alone. What is more, the resultant coating has a higher impact strength, is more flexible, and allows thicker coatings to be deposited. A

Apparently, the unoxidized copolymer functions to plasticize the partly oxidized polymer to improve the properties of the set coating as well as participating in the copolymerization reaction. Furthermore, the presence of the unoxidized material apparently reduces a tendency of the partly oxidized material to burn in the environment of heat to which it is subjected, so that less material is lost by burning than has been the experience previously.

The combination of the unoxidized and partly oxidized materials provides these beneficial results despite the fact that the two materials are normally considered incompatible. Nevertheless, if the materials are mixed and heated to a temperature of 120 to 150 F. prior to application, the unoxidized material will become dispersed in the partly oxidized material and its solvent to a degree which is sufiicient to deposit greater amounts of solids on the article to be coated. 'The resulting coating is also benefited to the extent of being more flexible, having a higheri'rnpact strength, and the like than coatings produced through the use of each of the ingredients individually.

Suitable solvents for the partly oxidized material include alkanols such as isopropanol and ethanol, petroleum naphthas having a boiling range of about 90 to 120 C., straight 'ru'n rnineral spirits having a boiling range of about 125 to 200 C., or hydrocarbonssuch as butane, pentane, behzene,toluene, xylene, cyclohexane, buten'es, pentenes,

chlorinated solvents or the like, alone or in admixture. Suificient solvent is present to provide'aconsisteney suit-v able for the type of application which is to be used. Where the material is to be sprayed, the solvent will normally be present in amounts of from 33 to. 100 parts by weight for every 100 parts by weight of the incompletely The coating composition may also include other addi- The increase in total solids from Example I was 1.74%.

material, 14.1% was the unoxidized copolymer, and 6.6% was the pigment. This material had a solvent containing three parts by weight of Solvesso 100 (containing xylenes and toluene) and one part by weight of isopropanol to bring the total up to 100%. This liquid composition was sprayed through an envelope of heat and flames at an object using an atomizing air pressure of p.s.i. One hundred and one grams of the material were used to apply a thickness of 5 /2 mils. This represented a deposition of 0.0544 mil per every gram or, conversely, required 18.36 grams to deposit one mil of thickness.

Example II The same amounts of the partly oxidized polymer and pigment were employed as in Example I, except that the amount of the unoxidized copolymer was increased to 9.31%. The total solids content was then 55.25% of which 76.8% was the partly oxidized material, 16.85% was the unoxidized material, and 6.35% was pigment.

When this composition was sprayed at an atomizing pressure of 40 p.s.i., 97 grams of the material provided a coating thickness of 6mils. Thus, the amount of'material required to deposit 1 mil of thickness was reduced to 16 grams, or an increase of 13.6% in deposition occurred as compared with Example 1.

Example III was held the same as in Example I, and the amount of tives. Typical among these is a pigment such as an oxide of chromium of iron or siliceous extender pigments, which can be present in amounts ranging from about 3 to 8% j by weight of the composition.

However the coating isapplied, it is advisable to preheat the surfacelto be coated, such preheat temperaturesusu- .ally ranging from 250m500 F;

With the improved coating compositionof the present invention, I have found that the liquid sprayed may have "a significantly higher solids content than could be 'employed using other butadiene-styrene copolymer combinations. For example, the total solids content of the composition can be as high as 50 to 75% by weight. This means that less amounts of the solvent have to bedisposed of either during or'after spraying, and less likelihood that the solvent will cause de fectsin the coating due to blistering.

A further description of the invention will be made in conjunction with the following specific exampleswhich appear solely for purposes of exemplification and not for the purpose of limiting'the scope of the invention.

of a partly oxidized butadiene-styrene copolymer containing from 75 to 85% butadiene andv 25 to 15% styrene, and

having an acid number of about 10. This'was combined with 7.57% of an unoxidized butadiene-styrene copolymer of the same type having a molecular weight of 8,000 to 10,000 and an iodine number of about 300, and an acid number of about 0. A chromium oxide pigment was added in the amount of 3.51% giving it a total solid content of 53.51% of which 79.3% was the slightly oxidized unoxidized copolymer was increased to 11.64%, thereby sentedan increase of 4.07% over the solids content of the composition of Example I. The solids content was divided between 73.7% of the partly oxidized material, 20.2% of the unoxidized material, and 6.1% of the pigment. "When this formulation Iwas applied at an atomizing pressure of 40 p.s.i., 84 grams of the material were sufficient to producea coating thickness of 5% mils. This meant that 15.5 gramsof the material were required to produce a mil ofcoating thickness on the average. The increase in deposition between this material and that of Example I, therefore, amounted to about 22%.

shortly thereafter contacted with a curing flame orother heat source sutficient to advance substantially the curing of the copolymer into its finallyset form. Y

It should beevident that various modifications can be from the scope ofthe-presentinvention. 7

I claim as my inventionz' 1. A composition settablebyr'heat into an impervious protective coating comprisingja mixture whose solids content contains from 5 to 40% of (a) a viscous liquid butadiene-styrene copolymer containing from to 85% butadiene and '15 to 25% styrene and from 60 to of (b) a partly oxidized butadiene-styrene copolymer containing from 75 to 85 butadiene and 15 to 25% styrene,

said partly oxidized polymer having been oxidizedto the extent of assimilating from about 5 to 20% of its weight in oxygen, and a solvent for (b). f

2. The composition of claim 1 in which the total solids range from 50to 75 by weight of the composition.

p 3. Compositions settable by heat into an impervious protective coating comprising a mixture whose solids content contains from 5 to 40% of (a) a viscous liquid butadiene-styrene copolymer containing from 75 to 85% made to the described embodiments without departing butadiene and to styrene, said copolymer having References Cited by the Examiner 2(1: acid nlllmber dof iullzsta tially 0 and tlo 95% of UNITED STATES PATENTS a par y oxi ize uta iene-styrene copo ymer containing from to butadiene and 15 to 25% styrene, 2855376 10/58 Show) et a1 260' 33'6 said partly oxidized copolymer having an acid number on 5 2876207 3/59 Hendefson 260-334 the order of 5 to 18, in combination with a solvent for (b). 2959619 11/60 Hutchinson 260-335 4. The composition-of claim 3 in which said solvent is 3036025 5/62 Hutchmson 260 33'4 XR a mixture of xylenes and an aliphatic alcohol. 1 MORRIS LIEBMAN, Primary Examiner. 

1. A COMPOSITION SETTABLE BY HEAT INTO AN IMPERVIOUS PROTECTIVE COATING COMPRISING A MIXTURE WHOSE SOLIDS CONTENT CONTAINS FROM 5 TO 40% OF (A) A VISCOUS LIQUID BUTADIENE-STYRENE COPOLYMER CONTAINING FROM 75 TO 85% BUTADIENE AND 15 TO 25% STYRENE AND FROM 60 TO 95% OF (B) A PARTLY OXIDIZED BUTADIENE-STYRENE COPOLYMER CONTAINING FROM 75 TO 85% BUTADIENE AND 15 TO 25% STYRENE, SAID PARTLY OXIDIZED POLYMER HAVING BEEN OXIDIZED TO THE EXTENT OF ASSIMILATING FROM ABOUT 5 TO 20% OF ITS WEIGHT IN OXYGEN, AND A SOLVENT FOR (B). 